ES2550203T3 - Easy opening container - Google Patents

Abstract

Easy-to-open two-piece package, whose container opening is sealed with a lid composed of a preferably transparent multilayer film, comprising a series of layers of a) a sealing layer (a), if any composed of several layers, based on at least one heat-sealable thermoplastic olefin homopolymer and / or copolymer, b) a first layer of an adhesion promoting agent (b), based on at least one olefin homopolymer and / or copolymer modified with polar organic groups, in a 0.03 to 0.5% by weight with respect to the homopolymer and / or copolymer, preferably 0.05 to 0.3% by weight, and if appropriate a homopolymer and / or copolymer of thermoplastic olefin, preferably the olefin homopolymer and / or copolymer of layer (a), c) a layer (c) based on at least one homopolyamide and / or copolyamide, d) a barrier layer (d), e) a layer (e) based in at least one homopolyamide and / or copolyamide, f) if appropriate a layer of adhesion promoting agent (f), g) if necessary a layer (g), if it is the case composed of several layers, based on at least one thermoplastic olefin homopolymer and / or copolymer, and h) a carrier layer (h) based on at least one thermoplastic polymer, the ratio of the strength of the sealing seam between the lid and the container and the bonding adhesion between the layer b) and the layer c) equal to a value between 1 , 8 and 4.5, preferably between 1.9 and 3, and the total thickness of the layer (a) and the layer (b) being a maximum of 16 μm, preferably 5 to 15 μm.

Description

image 1

Description

Easy opening container

The present invention relates to an easy-to-open two-piece container, where the container opening is sealed with a lid composed of a multilayer film, preferably transparent, comprising the series of layers:

a) a sealing layer (a), if necessary composed of several layers, based on at least one thermo-plastic thermoplastic olefin homopolymer and / or copolymer, b) a first layer of an adhesion promoting agent (b), based on at least one

10 homopolymer and / or copolymer of olefin modified with polar organic groups, in 0.03 to 0.5% by weight with respect to the homopolymer and / or copolymer, preferably in 0.05 to 0.3% by weight , and if appropriate a thermoplastic olefin homopolymer and / or copolymer, preferably the olefin homopolymer and / or copolymer of layer (a), c) a layer (c) based on at least one homopolyamide and / or copolyamide,

D) a barrier layer (d), e) a layer (e) based on at least one homopolyamide and / or copolyamide, f) where appropriate a second layer of adhesion promoting agent (f), g) if necessary one layer (g), if it is the case composed of several layers, based on at least one thermoplastic olefin homopolymer and / or copolymer, and

20 h) a carrier layer (h) based on at least one thermoplastic polymer,

the ratio of the strength of the sealing seam between the lid and the container and the bonding adhesion between the layer b) and the layer c) being equal to a value between 1.8 and 4.5, preferably between 1, 9 and 3, and the total thickness of the layer (a) and the layer (b) being a maximum of 16 µm.

25 In the food industry, products such as food, packaged in plastic containers consisting of a container and a lid are often offered, allowing the buyer to examine clearly and visibly, in particular through the lid, the product packaged in the container. At the same time, it is desirable that the packages can be opened in a controllable manner by applying a small and uniform force.

In the current state of the art numerous plastic containers are known whose lids are composed

30 by a multilayer film that has a heat sealable layer, which is applied by heat sealing over the opening of the container. To open these containers, the heat seal seam is usually broken. To facilitate opening, the material of the sealing layer of the lid film may have a composition such that the lid is attached to the container only removably. However, here the disadvantage is that the ability to remove the material from the sealing layer frequently

35 leads to unwanted cloudiness of the lid and reduced sealing resistance between the two elements of the package.

In EP 1749655 B1 an attempt was made to solve this problem by providing a multilayer film where a removable sealing layer material was not used, but rather weakened the cohesion of the layer adjacent to the sealing layer. The way to achieve this was to produce this layer from a polymer mixture of two incompatible polymer components. When a multilayer film with this structure is sealed as a lid against the opening of a second container element, when the container is opened, at least a part of the sealing layer is in the area of the sealing seam. sealing and a partial layer part of the adjacent layer, since the adjacent layer is split into two partial layers in its longitudinal direction by tearing (cohesion stripping). However, this often does not lead to a clean separation between the lid and the container, since it can also cause the lid to tear or tear out of the area of the sealing seam and by breaking the seam and , where appropriate, may remain

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Remains of the multilayer film in the packaged product, such as a packaged food, which is unpleasant for the consumer.

Therefore, there is a need for packages that are distinguished not only by a uniform controlled opening, but also by a clean break, that is limited to the area of the sealing seam, but nonetheless easier, during opening.

Thus, the objective of the present invention is to provide packages that are distinguished by a uniformly easy, controlled and very little destructive opening outside the area of the sealing seam in relation to the already known packages. In addition, there should be very good optical properties, such as transparency, especially of the lid.

This objective is achieved by providing the easy-to-open package according to the invention, which is characterized in that the opening of the container is sealed with a lid composed of a preferably transparent multilayer film, comprising the series of layers

a) a sealing layer (a), if necessary composed of several layers, based on at least one thermo-plastic thermoplastic olefin homopolymer and / or copolymer,

15 b) a first layer of an adhesion promoting agent (b), based on at least one olefin homopolymer and / or copolymer modified with polar organic groups, at 0.03 to 0.5% by weight with respect to homopolymer and / or copolymer, preferably 0.05 to 0.3% by weight, and if appropriate a thermoplastic olefin homopolymer and / or copolymer, preferably the olefin homopolymer and / or copolymer of layer (a) ,

C) a layer (c) based on at least one homopolyamide and / or copolyamide, d) a barrier layer (d), e) a layer (e) based on at least one homopolyamide and / or copolyamide, f) in case given a second layer of adhesion promoting agent (f), g) if necessary a layer (g), if it is the case composed of several layers, based on at least one

25 thermoplastic olefin homopolymer and / or copolymer, and h) a carrier layer (h) based on at least one thermoplastic polymer,

the ratio of the strength of the sealing seam between the lid and the container and the bonding adhesion between the layer b) and the layer c) being equal to a value between 1.8 and 4.5, preferably between 1, 9 and 3, and being the

30 total thickness of the layer (a) and the layer (b) of a maximum of 16 µm.

The easy-to-open packages according to the invention are especially distinguished because, when the package is opened, the multilayer film of the lid is delaminated in the area of the sealing seam between the layer (b) and the layer (c), so that the partial joint formed by the sealed layer (a) and the layer (b) of the multilayer film of the lid remains on the container in the form of a fragment of this partial union of torn layers and

35 delaminated corresponding to the width of the sealing seam.

In the sense of the present invention, the term "delamination" or "delamination capacity" means that the layers, that is according to the invention, the layer (b) and the layer (c) of the multilayer film of the lid, are joined together so that they can be separated from each other in a very little destructive way. In the sense of the present invention, the term "very little destructive" should be understood as, when separating

40 layers (b) and (c), tiny traces may remain as traces of one of the layers in each case another layer, so that the area of the open sealing seam has, at least briefly, a white color .

The delamination capacity between the "delaminable" layers is determined by the bonding bond. The method of determining bonding adhesion is described below in the description of the

45 present application, before the examples.

The determination of bonding adhesion is also used to select modified olefin homopolymers and / or copolymers suitable for the adhesion promoter layer (b), or to mix these polymeric components where appropriate with corresponding unmodified polymers so that the bonding adhesion between the layer (b) and the layer (c) is adjusted to the lowest bonding adhesion necessary in relation to the strength of the sealing seam.

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It is understood that the bonding bond between all other layers present in the multilayer film of the

The cover must also be greater than the bond adhesion between the layer (b) and the layer (c), but in particular the bond adhesion between the sealing layer (a) and the layer (b) as agent layer adhesion promoter. In a preferred embodiment of the package according to the invention, the sealing resistance between the two elements of the package, that is the container and the lid, is 25 -45 N / 15 mm, especially 30 -45 N / 15 mm

The determination of the sealing resistance is carried out according to the method described below. This

The method can also be applied to check if the polymeric materials selected for the formation of the sealing layer (a) and the container film have sufficient sealing strength.

The multilayer film used according to the invention is preferably transparent, that is, all the layers of the multilayer films used as a cover film are transparent. The determination of transparency, where appropriate, of each of the layers of the multilayer film used according to the invention,

15 is performed according to the method described below. If necessary, the multilayer film used according to the invention can be printed, at least in part.

In order to produce the sealing layer (a), if necessary composed of several layers, of the thermo-plastic thermoplastic olefin homopolymers and / or copolymers used according to the invention are suitable.

In order to produce the sealing layer (a), if it is composed of several layers, of the multilayer film used according to the invention, homopolymers and copolymers of olefin are suitable, preferably thermoplastic olefin homopolymers or copolymers of ethylene and / or propylene with, if necessary, additional α, β-unsaturated olefins of 6-10, ie 6, 7, 8, 9 or 10, carbon atoms. Suitable olefin homopolymers are preferably those selected from the group comprising

25 ethylene homopolymers (polyethylene, PE), preferably LDPE and HDPE, propylene homopolymers (polypropylene, PP) and mixtures of at least two of the cited polymers. With "LDPE" are designated low density polyethylenes, with a density of 0.86-0.93 g / cm3, and which are distinguished by a high degree of branching of the molecules. With "HDPE" high density polyethylenes are designated that have only a small branching of the molecular chain, the density being able to be between 0.94 and 0.97 g / cm3. As copolymers

The olefin copolymers of ethylene and propylene and copolymers of ethylene and / or propylene are preferably suitable, and at least one α-olefin of at least 6, preferably 6-10, and especially preferably 6-8, carbon atoms, and with very special preference copolymers of ethylene and / or propylene with at least one α-olefin selected from the group comprising hexene and octene, whose proportion in the olefin copolymers is preferably at most 25mol% and especially preferably as

Maximum of 15mol%, in each case with respect to the total weight of the olefin copolymer. As copolymers of ethylene and at least one α-olefin, LLDPE and / or mPE are suitable. With "LLDPE" linear ethylene copolymers of low density are designated, which are characterized by the presence of a linear main chain with side chains therein and with a density between 0.86 and 0.94 g / cm3. With "mPE" ethylene copolymers are designated which have been polymerized by metallocene catalysts and

40 preferably have a density between 0.88 and 0.93 g / cm3. Copolymers of propylene and ethylene are especially suitable as copolymers, the proportion of ethylene being up to 30% by weight.

With very special preference, the layer (a), if necessary composed of several layers, of the multilayer film used according to the invention is based on a polypropylene, preferably of structure

45, and / or in a propylene / ethylene copolymer.

The sealing layer (a) can be composed of one or several layers, if it is composed of several layers it is preferably composed of two layers, and if it is composed of several layers, the same type of homopolymer is preferably used and / or copolymer, especially the same homopolymer and / or copolymer.

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If the sealing layer (a) is composed of several layers, preferably all layers have the same thickness.

Preferably, the multilayer film used according to the invention has a lasting anti-fog effect.

Within the meaning of this invention, the term "durable anti-fog effect" is understood as an anti-fog effect of the multilayer film used according to the invention as a cover film with a largely unchanged intensity for a period of at least six months.

To achieve the anti-fog effect, the sealing layer (a), if necessary composed of several layers, of the

The multilayer film used according to the invention contains between 1.0% by weight and 12.0% by weight, based on the total weight of the sealing layer (a), of at least one anti-fog additive.

With special preference, the sealing layer (a) has between 1.5% by weight and 10.0% by weight and with very special preference between 3.0% by weight and 6.0% by weight with with respect to the total weight of the sealing layer (a), if composed of several layers, of at least one anti-fog additive.

In a sealing layer (a) composed of several layers, the proportion of the anti-fog additive preferably decreases from the outermost layer to the inner layers continuously and with special preference the anti-fog additive is found only in the outermost layer.

At least one additive selected from the group comprising alkoxylated and hydroxylated amines, alkoxylated and hydroxylated amides, polyol acid esters is preferably used as the anti-fog additive.

Fatty, preferably glycerol esters of fatty acids, esters, preferably monoesters, of sorbitan and at least one fatty acid, as well as in each case their corresponding salts.

Suitable alkoxylated and hydroxylated amines and as alkoxylated and hydroxylated amides are preferably those selected from the group comprising N, N-bis- (2-hydroxyethyl) tetradecylamine, bis (2-hydroxyethyl) pentadecylamine, bis (2-hydroxyethyl) hexadecylamine, bis (2 -hydroxyethyl) heptadecylamine, bis (225 hydroxyethyl) -octadecylamine, bis (2-hydroxyethyl) tetradecenylamine, bis (2-hydroxyethyl) -pentadecenylamine, bis (2-hydroxyethyl) hexadecenylamine, bis (2-hydroxyethyl) -heptadecylamine, bis ) octadecenylamine, caprylic acid diethanolamide, capric acid diethanolamide, lauric acid diethanolamide, myristic acid diethanolamide, palmitic acid diethanolamide, stearic acid diethanolamide, oleic acid diethanolamide, linolenic acid diethanolamide, and linolenic acid diethanolamide

30 arachidonic acid diethanolamide.

In the sense of this invention, "fatty acid polyol ester" means an ester of a polyvalent alcohol, that is, for example, a bivalent, trivalent, tetravalent or pentavalent alcohol, with at least one of the alcohol functions of one of such polyhydric alcohols esterified with an aliphatic, branched or linear, saturated or unsaturated fatty acid. If the alcohol functions of the polyvalent alcohol 35 esterified with fatty acids are various, these alcohol functions can be esterified with different fatty acids independently of each other. As preferred polyvalent alcohols there may be mentioned: ethylene glycol, glycerin (glycerol) and 1,4-butanediol. Glycerin is especially preferred. Thus, glycerol fatty acid esters comprise monoglycerides, diglycerides and triglycerides. The fatty acids are preferably selected from the group comprising caprylic, capric, lauric, myristic acids,

40 palmitic, stearic, oleic, linoleic, linolenic and arachidonic. Preferred polyol fatty acid esters are selected from the group comprising glycerin monostearate, glycerin distearate, glycerin monolaurate, glycerin dilaurate, glycerin monopalmitate, glycerin dipalmitate, glycerin monomyristate and glycerine dimiristate.

Suitable sorbitan esters are sorbitan monoesters, diesters, triesters and tetraesters,

Preferably sorbitan monoesters and at least one aliphatic, branched or linear, saturated or unsaturated fatty acid, for example caprylic, capric, lauric, myristic, palmitic, stearic, oleic, linolic, linolenic and arachidonic acids. A particularly preferred sorbitan monoester is sorbitan monolaurate.

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Preferably, the total layer thickness of the sealing layer (a), if necessary composed of several layers, and of the layer (b) is a maximum of 16 µm and preferably is between 5 and 15 µm, the thickness being 5 of the sealing layer (a) preferably at least 50% of the total thickness of the layer (a) and the layer (b).

In order to produce the first layer of adhesion promoting agent (b) of the multilayer film used according to the invention, at least 0.03-0.5% by weight, homopolymer and / or copolymer of thermoplastic modified, preferably in 0.05 -0.3% by weight with respect to the homopolymer and / or copolymer, with polar organic groups, preferably with organic acid groups 10 and / or organic anhydrides, especially with cyclic organic anhydride groups and with very special preference with maleic anhydride groups. The person skilled in the art is aware of methods to modify these thermoplastic polymers suitable for producing the layer of adhesion promoting agent (b). The modification is preferably carried out by grafting in the thermoplastic homopolymer or copolymer, especially preferably in an olefin homopolymer or copolymer, which is preferably formed in its

Most (in more than 50%) from an olefin, from which the polymer of the sealing layer (a) is also formed mostly (more than 50%), with particular preference in each case from propylene.

With very special preference, an olefin homopolymer or copolymer of the same type as that used as a polymer of the sealing layer is used to modify the adhesion promoting agent layer (b)

20 a). With very special preference a homopolymer or copolymer of ethylene or propylene modified with cyclic organic acid anhydride groups is used and with very special preference a homopolymer-copolymer of propylene or a propylene / ethylene copolymer modified as mentioned above with maleic anhydride groups .

Preferably the layer of adhesion promoting agent (b) of the multilayer film used according to the

The invention has a layer thickness of a maximum of 8 µ, with a special preference of a maximum of 5 µ and with a very special preference of a maximum of 3 µ.

If the bonding adhesion, determined according to the method mentioned below, between the first layer of adhesion promoting agent (b) and the adjacent polyamide layer (c) is too small, such that the seam strength ratio Sealing and bonding between the layer (b) and the layer (c) 30 is less than 1.8, it is possible, to sufficiently increase the bonding between these two layers, by mixing a homopolymer or copolymer of unmodified olefin that has served as the basis for the modification, preferably the graft. This is preferably a polypropylene or propylene copolymer also used to produce the grafted polymer of the adhesion promoting agent layer (b). By simple previous tests, the necessary bonding adhesion between the layer (b) and

35 the layer (c).

Homopolyamides and / or copolyamides, preferably selected from the group comprising aliphatic, partially aromatic and aromatic thermoplastic homopolyamides or copolyamides, are suitable for producing layer (c) and layer (e) of the multilayer film used according to the invention. These homopolyamides or copolyamides may be formed from aliphatic and / or cycloaliphatic diamines of 240 carbon atoms, such as hexamethylenediamine, and / or aromatic diamines of 6-10 carbon atoms, such as p-phenylenediamine, and from aliphatic dicarboxylic acids and / or aromatic of 6-14 carbon atoms, for example adipic, terephthalic or isoterephthalic acids. In addition, these homopolyamides or copolyamides can be produced from lactams of 4-10 carbon atoms, for example from εcaprolactam. Preferably the homopolyamides and / or copolyamides used according to the invention are

45 select from the group comprising PA 6, PA 12, PA 66, PA 6I, PA 6T, corresponding copolymers and mixtures of at least two of the mentioned polymers.

The thickness of the layers (c) and (e) is preferably identical and is between 1.0 and 6 µm, especially preferably between 2 and 4 µm.

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The multilayer film used according to the invention as a cover film has a layer (d) as a barrier layer, preferably as a gas barrier layer, attached in each case to the adjacent polyamide layer. With special preference, the layer (d) is a barrier layer against oxygen and / or against water vapor.

The layer (d) of the multilayer film used according to the invention is preferably based on or formed from at least one thermoplastic polymer selected from the group comprising ethylene-vinyl alcohol copolymers (EVOH), at least partially saponified polyvinyl acetates , polyvinylidene chloride (PVDC) and vinylidene chloride copolymers, preferably with a proportion of vinylidene chloride of at least 80% with respect to the total weight of the vinylidene chloride copolymer, or

10 a mixture of at least two of the mentioned polymers. With particular preference, the barrier layer is formed from at least one ethylene-vinyl alcohol copolymer.

The ethylene-vinyl alcohol (EVOH) copolymers used to produce the layer (d) are obtained by complete or incomplete hydrolysis of the corresponding ethylene-vinyl acetate (EVAc) copolymers. Preferably, completely saponified ethylene-vinyl acetate copolymers are used, with a

15 degree of saponification ≥ 98% and an ethylene ratio of 0.01-80 mol%, preferably 1-50 mol%, in each case with respect to the total weight of the ethylene-vinyl alcohol copolymer.

At least partially saponified polyvinyl acetates used to produce the layer (d) of the multilayer film used according to the invention are obtained by complete or incomplete hydrolysis of the corresponding polyvinyl acetates. At least partially saponified polyvinyl acetates

20 employees with special preference to produce layer (d) are selected from the group comprising fully saponified polyvinyl acetates (polyvinyl alcohols, PVOH), with a saponification degree> 98%, and partially saponified polyvinyl acetates, with a degree of Saponification of 75 to 98%, both inclusive.

Preferably the layer (d) of the multilayer film used according to the invention has a layer thickness of 1 µm to 10 µm, especially preferably 1.5 to 5 µm.

The layer (e) of polyamide is bonded, if necessary, by a layer of adhesion promoting agent (f) to the layer (g), if present, adjacent to it or to the carrier layer (h).

Preferably, the second layer of adhesion promoting agent (f) is based on at least one homopolymer and / or copolymer of thermoplastic modified olefin. Here you can also use the same

30 homopolymer and copolymer of modified thermoplastic olefin that used to produce the layer (b). With particular preference, the layer of adhesion promoting agent (f) is also based on at least one homopolymer or copolymer of ethylene or propylene modified with cyclic organic acid anhydride groups, especially preferably in a homopolymer or copolymer of ethylene or propylene modified with maleic anhydride groups.

Preferably, the layer of adhesion promoting agent (f) of the multilayer film used according to the invention has a layer thickness of at most 8 µm, especially preferably at most 5 µm and with very special preference at most 3 µm.

In another preferred embodiment, the multilayer film used according to the invention also has, for reasons of production technique, a layer (g), if any composed of several layers,

40 preferably composed of two layers, based on at least one thermoplastic olefin homopolymer or copolymer.

To produce the layer (g) of the multilayer film used according to the invention, the same type of thermoplastic homopolymers and copolymers is suitable as can also be used to produce the sealing layer (a). A thermoplastic olefin copolymer is preferred, preferably a copolymer of

45 propylene / ethylene.

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The layers of a layer (g) composed of several layers are preferably composed of the same type of homopolymer and / or copolymer, especially with the same homopolymer and / or copolymer.

Preferably, the layer (g) of the multilayer film used according to the invention has a layer thickness of at most 25 µm, with particular preference of at most 20 µm and with very special preference of 5 at most 15 µm.

If the layer (g) is composed of several layers, preferably all layers have the same thickness.

The multilayer film used according to the invention also has a transparent carrier layer (h), if necessary printed at least in part.

In order to produce the carrier layer (h) of the multilayer film used according to the invention, at least one thermoplastic polymer is preferably suitable.

The carrier layer (h) of the multilayer film used according to the invention is preferably based on at least one thermoplastic polymer selected from the group comprising homopolymers or copolymers of olefin, homopolyamides or copolyamides and homopolyesters or copolyesters. With special preference, the carrier layer (h) is based on at least one homopolyamide and / or copolyamide.

The same type of olefin homopolymers or copolymers can be used to produce the carrier layer (h) as can also be used to produce the sealing layer (a) of the multilayer film used according to the invention.

The same type of homopolyamides and copolyamides can be used to produce the carrier layer (h) as can also be used to produce the layers (c) and (e) of the multilayer film used according to the

20 invention.

The homopolyesters and / or copolyesters suitable for producing the carrier layer (h) of the multilayer film used according to the invention are preferably selected from the group comprising aliphatic, partially aromatic and aromatic thermoplastic amorphous homopolytersters and copolyesters. Such homopolyesters and copolyesters are derived from polyols, preferably diols, for example ethylene glycol or 1,4-butanediol, and dicarboxylic acids or derivatives of dicarboxylic acids, such as adipic, isoterephthalic and / or terephthalic acids. To produce the carrier layer (h) as homopolytersters and / or copolyesters, polycarbonates (PC) can also be used according to the invention. Polyesters that are derived from a polyol component and a dicarboxylic acid component are called homopolytersters. Suitable homopolyesters are preferably selected from the group comprising PET, PBA and PBT. "PET" refers to polyethylene terephthalate 30, which is prepared from ethylene glycol and terephthalic acid. With "PBA" polybutylene adipate is designated, which is prepared from butan-1,4-diol and adipic acid. "PBT" refers to polybutylene terephthalate, which is prepared from butan-1,4-diol and terephthalic acid. The preferably amorphous state is identified here with the prefix "A". An especially preferred amorphous homopolyester is APET (amorphous PET). Copolyesters are called polyesters which, in addition to a polyol component and a dicarboxylic acid component, contain at least one additional comonomer, preferably an additional polyol component. Preferred amorphous copolyesters are suitable copolyesters of an aromatic dicarboxylic acid, such as terephthalic acid, an aliphatic glycol, such as ethylene glycol, and at least one additional monomer, preferably at least one additional monomer selected from the group comprising branched, aliphatic, aromatic polyols and cycloaliphatic polyols. An amorphous copolyester especially

Preferred is derived from ethylene glycol, terephthalic acid and 1,4-cyclohexanedimethanol.

The carrier layer (h) of the multilayer film used according to the invention can be stamped and / or oriented, preferably oriented in a monoaxial or biaxial manner and especially preferably oriented in a biaxial manner.

The carrier layer (h) of the multilayer film used according to the invention preferably has a layer thickness of 10 µm to 100 µm, especially preferably 12 µm to 80 µm.

E11008542

10-14-2015

Preferably, the carrier layer (h) may be attached to the remaining layer junction of the multilayer film used according to the invention, preferably to the existing layer (g) or (f) or to the layer (e) of this film multilayer, by means of an adhesive layer composed of at least one coating adhesive, preferably a coating adhesive based on polyurethane and with

Especially preferred is a bi-component polyurethane adhesive.

The adhesive layer of the multilayer film used according to the invention preferably has a layer thickness of at most 10 µm, with particular preference of at most 5 µm and with very special preference of at most 3 µm.

The multilayer film used according to the invention preferably has a total layer thickness of 35 µm

10 to 200 µm, especially preferably from 40 µm to 150 µm, with very special preference from 45 µm to 120 µm, in particular from 50 µm to 100 µm and in particular preferably from 45 µm to 80 µm.

If necessary, the layers of the multilayer film according to the invention, preferably the sealing layer (a), may all contain at least one usual additive known to the person skilled in the art, preferably at least one additive selected from the group which comprises separating agents,

15 dyes, antioxidants and / or antistatic. Each of the layers may contain, in each case independently of each other, at least 0.01-20% by weight, preferably at least 0.1-10% by weight, in each case with respect to the total weight of an individual layer of at least one of the additives mentioned above.

Preferably, the layers (a), (b), (c), (d) and (e), as well as the layers (f) and (g), if applicable, of the

The multilayer film used according to the invention can be produced and processed partially or together in the form of an extruded sleeve film or a molten film.

Therefore, the production of the different layers (a), (b), (c), (d) and (e), as well as the layers (f) and (g), if any, of the multilayer film used according to the invention can be carried out by (co) extrusion, especially preferably by (co) extrusion of blown films or by (co) extrusion

25 laundry

The existing carrier layer (h) of the multilayer film used according to the invention can preferably be obtained by extrusion and can be attached to the remaining layer junction of the multilayer film, preferably to the layer (f) or (g), by a layer of adhesive.

After (co) extrusion, the different layers or layer joints or the multilayer film in total can (n) be stretched, that is, oriented.

If the sealing layer (a) is preferably provided with at least one anti-fog additive, this can preferably be done during the production of the layer (a). Here it should be taken into account that the incorporation of the sealing layer (a) with the anti-fog additive can be carried out by means of a mixture of the anti-fog additive or by a mixture with a basic mixture of the anti-fog additive used, in the polymer or layer 35 sealing (a), with the remaining proportion of the polymer (s) of the sealing layer (a). This mixture can be performed dry in the form of granulate / powder or granulate / granulate. However, it is also possible to add the anti-fog additive to the molten polymers for the sealing layer (a), preferably with a dosed addition in an extruder used for extrusion of the sealing layer (a). If, if necessary, at least one additional layer of the multilayer film used according to the invention contains the

At least one additional additive of those mentioned above, the incorporation of this additive is carried out analogously.

The multilayer film used according to the invention is suitable for producing packaging elements, preferably lids and packages of any kind.

An object of the present invention is an easy-to-open two-piece container, which has a lid

45 composed of the multilayer film described above as the first packaging element. Such an easy-to-open two-piece container preferably includes a container as a second container element.

E11008542

10-14-2015

The container, as a second container element of a container according to the invention, is preferably a tray or tray formed from a monolayer or multilayer film, preferably monolayer, composed of a thermoplastic polymer, which if necessary has a sealing layer (s), if necessary composed of several layers, formed from a thermoplastic thermoplastic polymer. Both the

The monolayer or multilayer film as the sealing layer (s), if any, composed of several layers are preferably transparent.

To produce the container, or at least the sealing layer (s) of the container used according to the invention, the same thermo-plastic thermoplastic olefin homopolymers and / or copolymers are suitable as those that can be used to produce the sealing layer (a) of The cover film. The sealing layer (s)

10 of the container used according to the invention is preferably based on the same polymer (s) as the sealing layer (a) of the cover film. Preferably, this is also applicable if the sealing layer (s) is composed of several layers.

The sealing layer (s) of the container used according to the invention preferably has a layer thickness ≤ 20 µm, particularly preferably between 1 and 12 µm and with very special preference between 2 and 11 µm and, if the

The sealing layer (s) is composed of several layers, preferably all layers have the same thickness.

The container of an easy-to-open two-piece container of this type is preferably formed from a film by thermoforming, especially by deep drawing. The container used according to the invention preferably has a peripheral edge that defines the size

20 of the opening of the container that is sealed with the lid.

Preferably, the easy-to-open package according to the invention includes as a second container element a container formed from a film, preferably monolayer, composed of at least one thermoplastic polymer selected from the group consisting of homopolytersters and copolyesters, homopolyamides and copolyamides and homopolymers and olefin copolymers, presenting the film given the

In this case, a sealing layer (s), if any, composed of several layers, based on a thermoplastic thermoplastic polymer.

In order to produce the film preferably monolayer of the container used according to the invention, the same homopolyesters and / or copolyesters, homopolyamides and / or copolyamides and / or homopolymers and / or thermoplastic olefin copolymers are used, which are also suitable for

30 produce the carrier layer (h).

The preferably monolayer film of the container used according to the invention preferably has a layer thickness of 100 to 1,200 µm, especially preferably 200 to 1,000 µm.

To produce the easy-to-open container according to the invention, the multilayer lid film used according to the invention is sealed over the opening of the container used according to the invention, preferably over the

35 peripheral edge of this container, in the form of a sealing seam.

Those skilled in the art already know the respective production processes and the corresponding usual process parameters in a generalized manner.

The sealing of the multilayer film used according to the invention as a cover for closing the opening of the container used according to the invention is preferably carried out for a maximum of 2 seconds, with

Especially preferably for a maximum of ≤ 1.5 seconds, preferably at a temperature within a range of 150 to 220 ° C, especially within a range of 180 to 200 ° C, and preferably at a pressure between ≥ 1.5 bar and ≤ 6 bar, with special preference between ≥ 2 bar and ≤ 5.5 bar.

The resistance of the sealing seam between the two elements of the package, that is the container and the composite lid of the multilayer film used according to the invention, is preferably at most 45

45 N / 15 mm, with special preference from 30 to 45 N / 15 mm.

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The determination of the sealing resistance, which corresponds to the resistance of the sealing seam, is carried out according to the method described below. This method can also be applied to check if the polymeric materials selected to form the sealing layer (a) have sufficient sealing strength.

The packages according to the invention are distinguished in that they can be opened in a controllable, easy and exact way, that is to say essentially without destruction of the layer (b), and at the same time they allow a uniform opening, which can be done at once without increasing the force applied.

To open the packages according to the invention it is not absolutely necessary to equip the lid with an opening aid. However, if an opening aid, preferably a tongue, is placed, it is preferably adjacent to the area of the seal seam of the package. The opening of the container to the area of the sealing seam is done by lifting the lid to this area or, if an opening aid is placed, using this opening aid. During the opening process, in the area of the sealing seam, the partial joint formed by the sealing layer (a) and the layer (b) is delaminated from the layer (c) in an essentially non-destructive manner, so that , in the area of the sealing seam, this partial union of

15 delaminated layers formed by layers (a) and (b) are torn off with considerable accuracy according to the width of the sealing seam and remain on the container in the form of a torn fragment. After this opening in the area of the sealing seam, the container lid can continue to be lifted or easily removed from the container.

The easy-to-open container according to the invention, preferably the container cover film and with special

Preferably, the carrier layer (h) of the multilayer cover film used according to the invention can be printed, at least in part, and / or be colored transparent.

The easy-to-open package according to the invention is preferably suitable as a food container, especially for food. Therefore, in the easy-to-open container a food is preferably packaged as a packaged product, which can be observed without any problem preferably through

25 of the transparent cover film used according to the invention.

Another object of the present invention is an easy-to-open container according to the invention for food, especially a perishable food container, preferably for fresh meat.

Bonding Adhesion Determination

Bonding adhesion is indicated by the separation force in [N / 15 mm] necessary to separate the

Partial joint formed by the sealing layer (a) and the layer (b) of the layer (c) of the multilayer film according to the invention, or corresponding layers of suitable multilayer comparative films. The separation of the partial joint formed by the sealing layer (a) and the layer (b) of the layer (c) is carried out here in a very little destructive manner, the two layers of the layer (c) being delaminated.

To determine the bond adhesion between the layer (b) and the layer (c) an envelope is placed in parallel

The other is a test tape of a multilayer film according to the invention and a test tape of a second monolayer film composed of a thermoplastic polymer, used in each case to produce the container used according to the invention, in each case with a width of 15 mm and a length of approx. 150 mm, placing the test tape of the multilayer film according to the invention with its sealing side, that is to say the sealing layer (a), on one of the sides of the second monolayer film. With a device

Sealing 40 seals the two tapes along the entire width of 15 mm. Next, the resulting sealed test tape is fixed in a tensile testing machine so that the layers to be separated from each other (layer (b) of layer (c)) form an angle of approx. 180º, and then they are separated. The maximum and average force for separation is determined along the measurement section. A computer controlled tensile testing machine is used as a measuring device for the test. For

In order to determine the bond adhesion, a force-travel diagram is drawn here. The force measured in N corresponds to the force necessary to completely separate the layers of the test tape to be separated from each other (layer (b) of layer (c)).

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The method is also applied to check if necessary if the polymeric materials selected to form the layer (b) allow sufficient delamination of the layer (c). In this way, the bonding adhesion between these two layers can also be determined without a previous seal against a monolayer or multilayer sheet or film serving as a container.

5 Determination of sealing resistance

The multilayer film used according to the invention as a cover film is suitable as a lid of a two-piece container according to the invention, which as a second container element includes a container. To produce such a container, the cover film can be sealed by means of the sealing layer (a) on the container, which if necessary has a sealing layer (s).

10 The sealing resistance is indicated by the separation force in [N / 15 mm] necessary to separate the container and the lid of such a container from one another.

The sealing resistance between the container and the lid is based on the sealing resistance between the sealing layer (a) of the multilayer film used according to the invention and the container, ie the film from which the container is produced . Therefore, it is sufficient to determine the sealing resistance between a monolayer

15 consisting of a sealing layer (a) and the container film. The method of determining the seal strength can also be applied to check if the polymeric materials selected to form the seal layer (a) and the container film have sufficient seal strength.

The determination of the sealing resistance is carried out as described in "Determination of the bonding adhesion": A test tape of a first film 20 consisting of the sealing layer (a) and a sealing tape are placed parallel to each other test of a second film, in each case with a width of 15 mm and a length of approx. 150 mm With a sealing apparatus the two tapes are sealed together along the entire width of 15 mm. The two test tapes provided with a sealing seam are fixed with their longer unsealed ends in a tensile testing machine, so that the tapes to be separated from each other form an angle of approx. 180º, and they separate from each other. The other unsealed ends 25 are not fixed at a certain angle. The measurement section or the measurement time is extended until the 15 mm sealing seam is opened. The maximum and average force for separation is determined along the measuring section of the sealed area. A computer controlled tensile testing machine is used as a measuring device for the test. The force measured in N corresponds to the force necessary to separate the two test tapes along the 15 mm sealing seam to separate a

30 from another.

The following examples and comparative examples serve to explain the invention, but should not be construed as limiting.

I. Chemical characterization of the raw materials used:

PP copolymer: Propylene / ethylene copolymer with 4.2% by weight of ethylene (point of

35 melting: 145 ° C, density: 0.905 g / cm3) EVOH copolymer: Ethylene-vinyl alcohol copolymer (ethylene ratio: 38 mol%) HV1: Modified PP copolymer with maleic anhydride PA-6: Polyamide 6 PUR: Polyurethane-based adhesive

40 PA-6 (BO): Biaxially oriented polyamide 6

II. Production of the multilayer film B1 used according to the invention as a cover film, or of a multilayer film V1 for comparative purposes

Multi-layer films B1 and V1 were produced as follows:

B1 or V1 multilayer films were first produced in each case in the form of a 7 film

45 layers (layers (a), (b), (c), (d), (e), (f), (g)) by coextrusion of blown films. The different layers mentioned above of the films thus obtained are in each case contiguous with each other in the order in which

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which are mentioned in table 1. The layer (g) of the film-like joints thus obtained was then coated with a carrier layer (h) by a polyurethane-based adhesive, so that, including the resulting adhesive layer , a multilayer film B1 or V1 of 9 layers (B1) was obtained. The multilayer films B1 or V1 in each case have the layer structure according to Table 1 below and a total layer thickness of 55 µm or 58.3 µm. All data on percentages in Table 1 are always percentages by weight.

Table 1 - B1 or V1 multilayer film

Layer structure (B1 and V1)

Raw material B1 layer film [µm] Layer thickness V1 [µm]

Sealing layer (a) composed of two layers of equal thickness

PP copolymer 10 (5/5) 15 (7.5 / 7.5)

Adhesion promoting agent layer (b)

HV-1 2.8 2.8

Layer (c)

PA-6 3 3

Barrier layer (d)

EVOH 3.5 3.5

Layer (e)

PA-6 3 3

Adhesion promoting agent layer (f)

HV-1 2 2

Layer (g) composed of two layers of equal thickness

PP copolymer 12 (6/6) 12 (6/6)

Adhesive layer (i)

PUR 2 2

Carrier layer (h)

PA-6 (BO) fifteen fifteen

III Determination of bond adhesion or sealing strength (of seam)

10 The multilayer film B1 or V1 was sealed at a temperature of 180 ° C (sealing time: 0.5 s; sealing pressure: 5 bar; width of the film tape: 15 mm) against a molten PP of 500 µm thickness and then the force to remove the film was determined according to DIN 55529.

To determine the bonding adhesion between layers (b) and (c), the multilayer film B1 is sealed against 500 µm of PP as described above. When removed, the film separates between layers (b) and (c) (the junction of the

15 layers (a) and (b) remain on the 500 µm PP sheet) and the force applied is measured.

To determine the bonding adhesion between the layers (b) and (c), the multilayer film V1 is also sealed against 500 µm as described above. However, when the film is removed it breaks.

To determine the strength (of the seam) of sealing the layer (a) on the PP, a corresponding film is manufactured without the layers (c) to (g). This film is sealed as described above against 500 µm of PP and

20 withdraws. The force measured here corresponds to the resistance of the sealing seam of the layer (a) on the PP film. The measured value was for example B1 and for comparative example V1 of 31 and 32 N / 15 mm respectively.

Table 2 shows the results of the tests.

25

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Table 2

Test results:

Ex.

Bonding bond between layers (b) and (c) Seam Strength Sealing Quotient of the strength of the sealing seam and the bonding bond between the layers (b) and (c)

B1

15 N / 15 mm 31 N / 15 mm 2.1 one)

V1

- 32 N / 15 mm - 2)

1) The multilayer film is delaminated in the area of the sealing seam, whereby a partial joint formed by the sealing layer (a) and the layer (b) is torn off according to the width of the sealing seam in It forms a fragment of the partial junction and remains on the PP tray. 2) When removed, the multilayer film is broken, so that it is not possible to determine the ratio of the strength of the sealing seam and the bonding bond.

Claims (13)

image 1  Claims 1. Easy-to-open two-piece container, whose container opening is sealed with a lid composed of a preferably transparent multilayer film, comprising a series of 5 layers of a) a sealing layer (a), if necessary composed of several layers, based on at least one thermo-plastic thermoplastic olefin homopolymer and / or copolymer, b) a first layer of an adhesion promoting agent (b), based on at least one homopolymer and / or copolymer of olefin modified with polar organic groups, in a 0.03 to a 10 0.5% by weight with respect to the homopolymer and / or copolymer, preferably 0.05 to 0.3% by weight, and if appropriate a homopolymer and / or copolymer of thermoplastic olefin, preferably the homopolymer and / or olefin copolymer of layer (a), c) a layer (c) based on at least one homopolyamide and / or copolyamide, d) a barrier layer (d), E) a layer (e) based on at least one homopolyamide and / or copolyamide, f) where appropriate a second layer of adhesion promoting agent (f), g) where appropriate a layer (g), if it is the case composed of several layers, based on at least one homopolymer and / or copolymer of thermoplastic olefin, and h) a carrier layer (h) based on at least one thermoplastic polymer, the ratio of the strength of the sealing seam between the lid and the container and the bonding adhesion between the layer b) and the layer c) being equal to a value between 1.8 and 4.5, preferably between 1, 9 and 3, and the total thickness of the layer (a) and the layer (b) being a maximum of 16 µm, preferably 5 to 15 µm.

A container according to claim 1, characterized in that the sealing layer (a) of the multilayer film is based on at least one homopolymer or copolymer of ethylene and / or propylene, preferably at least one propylene copolymer and up to 30 % by weight of ethylene.

3. Package according to claim 1 or 2, characterized in that the sealing layer (a) is composed of several layers, preferably two layers.

Package according to one of claims 1 -3, characterized in that the layer thickness of the sealing layer (a) is at least 50% of the total thickness of the layer (a) and the layer (b).

5. Package according to one of claims 1 -4, characterized in that the resistance of the sealing seam between the lid and the container is between 25 and 45 N / 15 mm. A package according to one of claims 1 to 5, characterized in that the sealing layer (a) is provided with at least one anti-fog additive.

7.

Container according to claim 6, characterized in that the sealing layer (a) has between 1.5% by weight and 10.0% by weight, preferably between 3.0% by weight and 6.0% by weight , of at least one anti-fog additive, with respect to the total weight of the sealing layer (a).

8.

Packaging according to claim 7, characterized in that the sealing layer (a) is provided with

At least one anti-fog additive selected from the group comprising alkoxylated amines, alkoxylated amides, polyol esters of fatty acids, preferably glycerol esters of fatty acid, esters, preferably monoesters, of sorbitan and at least one fatty acid, the anti-fog effect being preferably lasting. image2 A package according to claim 7, characterized in that the proportion of the anti-fog additive in a sealing layer (a) composed of several layers decreases continuously from the outermost layer to the innermost layers, and preferably is only in The outermost layer A container according to any of the preceding claims, characterized in that the layer (b) is based on a homopolymer or copolymer of ethylene and / or propylene, preferably a modified propylene / ethylene copolymer, preferably grafted, with organic acid groups and / or organic acid anhydride groups, preferably cyclic organic acid anhydride groups. 11. Package according to any of the preceding claims, characterized in that the barrier layer (d) 10 is a gas barrier layer, preferably an oxygen barrier layer, which is based on at least one thermoplastic polymer selected from the group comprising ethylene-vinyl alcohol copolymers and vinylidene chloride copolymers, preferably at least one copolymer of ethylene-vinyl alcohol. 12. Packaging according to any of the preceding claims, characterized in that the layers (c) and (e) 15 are based on at least one homopolyamide and / or copolyamide selected from the group comprising thermoplastic, aliphatic, partially aromatic and aromatic homopolyamides or copolyamides, preferably on a homopolyamide or copolyamide formed from an aliphatic and / or cycloaliphatic diamine of 2-10 carbon atoms and / or aromatic diamine of 6-10 carbon atoms and from an aliphatic and / or aromatic dicarboxylic acid of 6-14 carbon atoms. 13. Packaging according to any of the preceding claims, characterized in that the carrier layer (h) is based on at least one thermoplastic polymer selected from the group comprising olefin homopolymers or copolymers, homopolyamides or copolyamides and homopolyesters or copolyesters. 14. Package according to any of the preceding claims, characterized in that the container of the The package is formed from a film, preferably monolayer, composed of a thermoplastic polymer selected from the group comprising a homopolyester and copolyester, a homopolyamide and copolyamide and a homopolymer and copolymer of olefin, the film having a sealing layer, if appropriate. (s) based on a heat-sealable thermoplastic polymer, preferably in a polymeric material identical to the polymeric component of the layer of 30 heat sealed.

fifteen.

Packaging according to claim 14, characterized in that the film and / or at least its sealing layer (s) is based on a copolymer of propylene and / or ethylene.

16.

Packaging according to any of the preceding claims, characterized in that the package is a

food container, preferably a perishable food container and with special preference for fresh meat. 17. Package according to any of the preceding claims, characterized in that the package is transparent.